SAN FRANCISCO (CBS SF) – After finding nearly 500 seabirds coated in an unknown substance in January, the International Bird Rescue has released 86 cleaned and healthy birds back into the wild so far.

Fifty-seven of them were set free Saturday at Fort Baker in an unpublicized release, and the nonprofit said Monday they may release more later this week on Wednesday or Thursday.

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Bird rescue executive director Barbara Callahan said there are still 132 birds in their care, however, which is a huge task. Those birds are currently in various stages of recovery and waterproofing, she said.

East Bay Regional Park District personnel continue to search for impacted birds, but Callahan said the crisis appears to be slowing down as no additional contaminated birds have been located since Jan. 22.

They first started appearing on or near the shores of the East Bay on Jan. 16, and some birds have also been found on the Peninsula.

Out of 493 contaminated birds, at least 170 of them were already dead, according to a prepared statement from the state Department of Fish and Wildlife. At least 102 more died in care, according to the nonprofit.

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The unknown substance coating the birds still hasn’t been identified, according to fish and wildlife spokeswoman Mary Fricke, but the agency has a team of scientists working on the issue.

“It’s a very long, in depth process, especially when you don’t know what the substance is,” Fricke said. “They’ve ruled out a couple of things, but the science takes time.”

“It’s not just done in 40 minutes like on CSI,” Fricke said.

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